Schunk-USA had almost completed the construction of a beautiful new manufacturing facility in Morrisville, NC. The network designer had put considerable thought into designing the data infrastructure for future bandwidth requirements and projected personnel growth. The company wanted the same foresight to be part of the DNC network infrastructure, so as to avoid having to make major or minor changes to its basic topology in any future expansion.

At this point decisions had already been made about where the machines would be physically located and what type of DNC software would be installed. Now it was time for the vendors to take measurements, study the installation environment, ensure that their data packages would work with Schunk-USA's controllers, and give accurate bids on the DNC network installation. A review of the first few bids indicated that the infrastructure installation was going to be a large part of the total cost. Factors driving the cost up included installation equipment, such as lift rentals, and the type of environment -- high voltage machines, lights with ballasts, and bus ducts. Schunk-USA needed a system that would allow it to bypass all these infrastructure issues and conform to the original intent of planning for future growth.

When Schunk-USA first looked at a wireless solution, it was cost prohibitive and not what would truly be considered a complete wireless system. The industry did have two options. The first -- wireless from server to serial port server, then cables from serial port server to the controller on the machines -- did not reduce the installation cost, and did not solve the infrastructure issues with running cables in a manufacturing environment. The second -- wireless from serial port server to the individual machines -- was closer to what the company wanted and did solve some installation problems, notably the high voltage concerns and lift rentals. But cost was still an issue, with a PC at each CNC machine and two wireless devices for each machine, one for the port on the serial server and the second on the CNC controller. Yes, it was a solution -- but not the one Schunk-USA needed.

Then Schunk-USA's IT department came up with a winning solution: wireless from the DNC server to the machine on the floor, without a PC at each work area. This solution required only one wireless device per machine and in the long run, was less expensive than running cables.

Here is how Schunk-USA did it:

First, a wireless site survey needed to be completed. The current location, less than one mile from the airport, was cause for concern. Would the radar and radio equipment cause problems with plans for a wireless network? No -- a good site survey cleared up any false notions about airport interference.

The next step was an equipment list. The PCs at the controllers were eliminated with Ethernet client bridges, which require no user interaction, and all operator training took place on the machine controller. The Ethernet client bridges connect wireless to an access point, a wireless hub device mounted high above the shop floor. The access point is connected directly to the DNC server. The serial port server was replaced with a software application that runs on the DNC server along with the DNC software package.

Where did Schunk-USA actually save money?

• First, by eliminating the serial port server, and replacing it with a software application.


• Second, the access point did not need an electrical outlet installed at the ceiling, since power is provided by an extra pair of wires in the Ethernet cable and an adapter made for this purpose.


• Third, by removing all PCs attached to the CNC machine controller, and installing Ethernet client bridges.


• Fourth, Ethernet client bridges do not require special voltages and can work off of 110 volts or 220 volts.

How about adding future machines? The only cost associated with adding more machines is about $250 per machine, not including the additional port for the CNC software. The installed infrastructure can handle at least 60 machines before there is degradation in performance.

How successful is the new system? Very successful; there have been no problems since the installation was completed. Training was easy, because the machine operators needed no training on new equipment; all training was based around the machine controller. The biggest problem during installation was coordination between the CNC software company and the wireless equipment manufacturer.

Indeed, Schunk-USA has created a wireless CNC network in a way that it has not been done before: designing a quality CNC network with one eye on the purse, and the other looking toward the future.